Anti-torque nozzle system with internal sleeve valve for a rotorcraft

ABSTRACT

The system of the present application includes a duct for receiving airflow from within a duct portion of a tailboom. The airflow is a mixture of fan driven air and engine exhaust. The system includes a fixed nozzle assembly with an anti-torque nozzle, a pro-torque nozzle and a thrust nozzle. A rotating sleeve valve is located within the fixed nozzle assembly. The rotating sleeve valve located within the fixed nozzle assembly and is configured to selectively redirect airflow into one or more of the anti-torque nozzle, the pro-torque nozzle and the thrust nozzle.

TECHNICAL FIELD

The present application relates to rotorcraft. In particular, thepresent application relates to propulsive anti-torque systems forrotorcraft.

DESCRIPTION OF THE PRIOR ART

A classic helicopter configuration includes a tail rotor for selectivelyproducing a torque upon the helicopter. Helicopters having a single mainrotor require a torque canceling device for controlling torque reactingon the airframe from the main rotor. Typically, the torque cancelingdevice is a tail rotor powered by the engine via a tail rotordriveshaft. Conventional tail rotors are unable to provide propulsiveforce to the helicopter.

Although the developments in helicopter torque systems have producedsignificant improvements, considerable shortcomings remain.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the system of the presentapplication are set forth in the appended claims. However, the systemitself, as well as a preferred mode of use, and further objectives andadvantages thereof, will best be understood by reference to thefollowing detailed description when read in conjunction with theaccompanying drawings, in which the leftmost significant digit(s) in thereference numerals denote(s) the first figure in which the respectivereference numerals appear, wherein:

FIG. 1 is a perspective view of a rotorcraft having a propulsiveanti-torque system according to the preferred embodiment of the presentapplication;

FIG. 2 is a partial cut-away side view of the rotorcraft of FIG. 1;

FIG. 3 is a schematic view of a selected portion of the rotorcraft ofFIG. 1;

FIG. 4 is a perspective view of the propulsive anti-torque systemaccording the preferred embodiment of the present application;

FIG. 5 is a side view of the propulsive anti-torque system of FIG. 4;

FIG. 6 is a top view of the propulsive anti-torque system of FIG. 4;

FIG. 7 is an additional side view of the propulsive anti-torque systemof FIG. 4;

FIG. 8 is a perspective view of a rotating sleeve valve assembly of thepropulsive anti-torque system of FIG. 4; and

FIG. 9 is cross-sectional view of the propulsive anti-torque system,taken along the section lines IX-IX shown in FIG. 6.

While the system of the present application is susceptible to variousmodifications and alternative forms, specific embodiments thereof havebeen shown by way of example in the drawings and are herein described indetail. It should be understood, however, that the description herein ofspecific embodiments is not intended to limit the method to theparticular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the application as defined by the appendedclaims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Illustrative embodiments of the system of the present application aredescribed below. In the interest of clarity, not all features of anactual implementation are described in this specification. It will ofcourse be appreciated that in the development of any such actualembodiment, numerous implementation-specific decisions must be made toachieve the developer's specific goals, such as compliance withsystem-related and business-related constraints, which will vary fromone implementation to another. Moreover, it will be appreciated thatsuch a development effort might be complex and time-consuming but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

In the specification, reference may be made to the spatial relationshipsbetween various components and to the spatial orientation of variousaspects of components as the devices are depicted in the attacheddrawings. However, as will be recognized by those skilled in the artafter a complete reading of the present application, the devices,members, apparatuses, etc. described herein may be positioned in anydesired orientation. Thus, the use of terms such as “above,” “below,”“upper,” “lower,” or other like terms to describe a spatial relationshipbetween various components or to describe the spatial orientation ofaspects of such components should be understood to describe a relativerelationship between the components or a spatial orientation of aspectsof such components, respectively, as the device described herein may beoriented in any desired direction.

The propulsive anti-torque system of present application is configuredto operate in an aircraft, the aircraft having with a propulsion systemwith a variable pitch fan installed approximate to an engine in theaircraft. The fan is driven directly from the main rotor drive via ashort shaft. The configuration and location of the fan allows theprimary exhaust from the engine to be mixed with the air flow from thefan. The mixed air flow from the fan and the engine passes through thetail boom and out the propulsive anti-torque system. All embodiments ofthe system of the present application may be configured in both mannedand unmanned aircraft.

Referring to FIGS. 1 and 2, aircraft 101 includes a fuselage 109 and alanding gear 121. A rotor system 105 is configured to receive cyclic andcollective control inputs thus enabling aircraft 101 to make controlledmovements. For example, a collective control input changes the pitch ofeach rotor blade 123 collectively. In contrast, a cyclic control inputsselectively changes the pitch of individual rotor blades according to arotation position. For example, as rotor blades 123 rotate, a cyclicinput can increase the lift on one side of aircraft 101 and decrease onthe other side of the aircraft 101, thus producing a lift differential.In this manner, cyclic control inputs can be made to control the pitchand roll of aircraft, as well as to produce various tilting maneuvers.Even though the preferred embodiment is shown with four rotor blades123, it should be appreciated that alternative embodiments may usegreater or fewer rotor blades.

In the preferred embodiment, aircraft 101 includes a fixed wing 107extending from each side of fuselage 109. Fixed wing 107 is configuredto provide supplemental lift to aircraft 101 during forward flight.During forward flight, wing 107 produces lift, thereby reducing thelifting responsibilities of rotor system 105. The supplemental liftprovided by wing 107 acts to reduce vibration, as well as improve therange and efficiency of aircraft 101. It should be appreciated thatalternative embodiments of aircraft 101 may not include wing 107. Thepreferred embodiment of aircraft 101 also includes tail fins 119 whichprovide aerodynamic stability during flight. It should be appreciatedthat tail fins 119 may take on a wide variety of configurations. Forexample, tail fins 119 may be replaced with any combination ofhorizontal and vertical fins.

Aircraft 101 further includes an engine 111 that provides power to rotorsystem 105 via a transmission 115. Engine 111 is also configured toprovide power to a fan 113. Fan 113 provides compressed airflow topropulsive anti-torque system 103, via a duct 117. In the preferredembodiment, fan 113 has variable pitch fan blades so that flight systemcontrols can control airflow produced by fan 113. Propulsive anti-torquesystem 103 is configured to selectively provide aircraft with a forwardthrust vector, an anti-torque vector, and a pro-torque vector, asdescribed in further detail herein.

Referring now to FIG. 3, a portion of aircraft 101 is schematicallyshown. Propulsive anti-torque system 103 receives compressed air flowvia duct 117. Duct 117 is interior to a tailboom 133 (shown in FIG. 2).During operation, inlet air 129 a enters an inlet 125 and is acceleratedthrough fan 113. Fan accelerated air 129 b travels through a duct systemaround engine 111 to a mixer portion 127 of duct 117. Exhaust air 129 cis expelled from engine 111 and travels to mixer portion 127. Mixerportion 127 is a daisy-type nozzle that provides shear layers fordisrupting airflow so as to facilitate mixing of fan accelerated air 129b and exhaust air 129 c so as to produce mixed air 129 d. The mixing ofthe hot exhaust air 129 c with the cool fan accelerated air 129 b actsto reduce the temperature of exhaust air 129 c, thereby reducing theinfrared (IR) signature of aircraft 101. External acoustic signature isalso reduced because the fan and engine components are locatedinternally and sound is dampened in duct 117, before mixed air 129 dexits propulsive anti-torque system 103. The mixing also recovers heatenergy from the exhaust to develop additional useful thrust over that ofthe fan alone.

Referring now to FIGS. 4-9, propulsive anti-torque system 103 is shownin further detail. System 103 includes a diverter 411 which is in fluidcommunication with duct 117. System 103 further includes a fixed nozzleassembly 401 having a various nozzles for selectively producing a thrustcomponent in single or multiple directions. Fixed nozzle assembly 401includes an anti-torque nozzle 403, a pro-torque nozzle 405, and athrust nozzle 407. A rotating sleeve valve 419 is located concentricallywith fixed nozzle assembly 401. In the preferred embodiment, diverter411 is integral to rotating sleeve valve 419 such that rotation ofrotating sleeve valve 419 results in rotation of diverter 411. Rotatingsleeve valve 419 is configured to be selectively rotated by a rotaryactuator spindle 409. During operation, mixed air 129 d travels intodiverter 411 from duct 117. From diverter 411, mixed air 129 d travelsthrough downstream portions of rotating sleeve valve 419 (shown in FIGS.8 and 9). Rotating sleeve valve 419 selectively redirects mixed air 129d into one or more of anti-torque nozzle 403, pro-torque nozzle 405, andthrust nozzle 407.

Referring to FIG. 8, rotating sleeve valve 419 is rotatably mountedinside fixed nozzle assembly 401 such that a forward sleeve opening 431of diverter 411 is concentric with duct 117. Rotating sleeve valve 419includes a scoop 433 for aerodynamically turning mixed air 129 d intoselected nozzles of the fixed nozzle assembly 401. A sleeve vane 421 ispreferably fixedly located in a scoop opening 429 of scoop 433, so as tofacilitate the turning of mixed air 129 d. In an alternative embodiment,sleeve vane 421 may be configured to selectively rotate so as toaccommodate changes in flow characteristics of mixed air 129 d. Actuatorspindle 409 is located on an aft portion of rotating sleeve valve 419.Rotating sleeve valve 419 is operably associated with an actuator 435.Actuator 435, which is schematically shown in FIG. 8, is configured toselectively rotate rotating sleeve valve 419, via spindle 409, intodesired positions. Positioning of rotating sleeve valve 419 ispreferably controlled by an aircraft flight control computer, but mayalso be controlled by manual inputs by the pilot. In the preferredembodiment, actuator 435 is electric. However, it should be appreciatedthat actuator 435 can be a wide variety of devices capably ofselectively positioning rotating sleeve valve 419, via actuator spindle409, into desired positions.

Referring again to FIGS. 4-9, rotating sleeve valve 419 directs mixedair 129 d from diverter 411 into one or more nozzles on fixed nozzleassembly 401. Anti-torque nozzle 403 is preferably elliptically shapedand protrudes in an outboard direction from the main body portion offixed nozzle assembly 401. In alternative embodiments, anti-torquenozzle 403 can be of a wide variety of shapes, such as trapezoidal.Anti-torque nozzle 403 preferably has one or more anti-torque vanes 423for directing the flow of mixed air 129 d in an anti-torque direction.In the preferred embodiment, each anti-torque vane 423 is fixed to theinterior side walls of anti-torque nozzle 403. In alternativeembodiments, each anti-torque vane 423 may be articulated such that eachvane 423 is rotatable on a generally horizontal axis so as toselectively contribute pitch control of aircraft 101. During operation,rotating sleeve valve 419 is positioned to direct air throughanti-torque nozzle 403, so as to produce an anti-torque vector 413 dueto the propulsive forces from air 129 d being directed throughanti-torque nozzle 403. Aircraft 101 is configured such that rotorsystem 105 rotates in a counter clockwise direction 131, as shown inFIG. 1. In such a configuration, anti-torque vector 413 acts to canceltorque induced upon aircraft from the rotation of rotor system 105 incounter clockwise direction 131. Furthermore, anti-torque vector 413 isselectively generated for yaw maneuvering and yaw stability, in additionto anti-torque control. It should be appreciated that other embodimentsof aircraft 101 may have a rotor system which rotates is a clockwisedirection (opposite from counter clockwise direction 131). In such aconfiguration, propulsive anti-torque system 103 would be configuredsuch that anti-torque nozzle 403 would be on the opposite side ofaircraft 101.

Pro-torque nozzle 405 is preferably elliptically shaped and protrudes inan outboard direction from the main body portion of fixed nozzleassembly 401. In alternative embodiments, pro-torque nozzle 405 can beof a wide variety of shapes, such as trapezoidal. Pro-torque nozzle 405preferably has one or more pro-torque vanes 425 for directing the flowof mixed air 129 d in the desired pro-torque direction. In the preferredembodiment, each pro-torque vane 425 is fixed to the interior side wallsof pro-torque nozzle 405. In alternative embodiments, each pro-torquevane 425 may be articulated such that each vane 425 is rotatable on agenerally horizontal axis so as to selectively contribute to pitchcontrol of aircraft 101. During operation, rotating sleeve valve 419directs air through pro-torque nozzle 405 to produce a pro-torque vector415. Furthermore, pro-torque vector 415 is selectively generated for yawmaneuvering and yaw stability.

Thrust nozzle 407 is preferably scoop shape so as to extend upward andtoward an aft direction, as shown in FIG. 5. Thrust nozzle 407preferably includes a thrust vane 427 for directing the flow of mixedair 129 d in the desired thrust direction. In the preferred embodiment,thrust vane 427 is fixed to the interior side walls of thrust nozzle407. In alternative embodiments, thrust vane 427 may be articulated suchthat thrust vane 427 is rotatable. During operation, rotating sleevevalve 419 directs air through thrust nozzle 407 to produce a forwardthrust vector 417. Forward thrust vector 417 is selectively generated tocontribute to forward propulsion of aircraft 101.

In operation, rotating sleeve valve 419 is selectively rotated to directmixed air 129 d into one or more of anti-torque nozzle 403, pro-torquenozzle 405, and thrust nozzle 407. For example, sleeve valve 419 may bepositioned to direct all of mixed air 129 d into anti-torque nozzle 403to produce anti-torque vector 413. Similarly, sleeve valve 419 may bepositioned to direct all of mixed air into pro-torque nozzle 405 toproduce pro-torque vector 415. Similarly, sleeve valve 419 may bepositioned to direct all of mixed air into thrust nozzle 407 to produceforward thrust vector 417. In addition, sleeve valve 419 may be actuatedso as to direct mixed air 129 d into both anti-torque nozzle 403 andthrust nozzle 407 simultaneously so as to produce a resultant vectorwhich is a combination of anti-torque vector 413 and forward thrustvector 417. Sleeve valve 419 may be rotated so as to selectively adjustthe proportion of mixed air 129 d that travels through anti-torquenozzle 403 and thrust nozzle 407, thereby changing the resultant vectorthat forms from the combination of anti-torque vector 413 and forwardthrust vector 417. For example, 30% of mixed air 129 d may be directedthrough anti-torque nozzle 403 with 70% of mixed air 129 d beingdirected through thrust nozzle 407, so as to produce a resultant vectorforce that is 30% of anti-torque vector 413 and 70% forward thrustvector 417. In a similar manner, sleeve valve 419 may be actuated so asto simultaneously direct mixed air 129 d into both pro-torque nozzle 405and thrust nozzle 407 so as to produce a resultant vector which is acombination of pro-torque vector 415 and forward thrust vector 417.

Referring to FIG. 9, system 103 is depicted in a cross-sectional viewwith sleeve valve 419 positioned to direct airflow through thrust valve407. A bearing 437 a is located between diverter 411 and tailboom 133.In the preferred embodiment, diverter 411 is integral with rotatingsleeve valve 419 such that diverter 411 rotates with rotating sleevevalve 419. However, it should be appreciated that alternativeembodiments can be configured with diverter 411 as a stationary separatestructure from rotating sleeve valve 419. A bearing 437 b is locatedbetween rotating sleeve valve 419 and fixed nozzle assembly 401 tofacilitate rotational movement therebetween. Similarly, a bearing 437 cis located between spindle 409 and fixed nozzle assembly 401.

The system of the present application provides significant advantages,including: (1) increasing the speed of the aircraft; (2) blade loadingand flapping are significantly reduced; (3) the margins for hub andcontrol loads are improved; (4) the quality of the ride at high speedsis significantly improved; (5) the noise level is significantly reduced;(6) system complexity is greatly reduced; (7) the infrared (IR)signature of the rotorcraft is significantly reduced, because theprimary engine exhaust is highly diluted when mixed with the air flowfrom the fan; (8) the acoustic signature of the rotorcraft is greatlyreduced, because both the primary engine and the propulsive anti-torquesystem are internal to the tail boom of the rotorcraft; (9) therotorcraft is significantly safer for personnel during groundoperations, because both the primary engine and the propulsiveanti-torque system are internal to the tail boom of the vehicle, therebyeliminating the possibilities of exposure to hot exhaust gasses or tailrotor strikes; and (10) anti-torque thrust is provided without the cost,weight, and complexity of a tail-rotor type device or a thrust typedevice that uses a fan driven by a secondary drive system.

The particular embodiments disclosed above are illustrative only, as theapplication may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. Furthermore, no limitations are intended to thedetails of construction or design herein shown, other than as describedin the claims below. It is therefore evident that the particularembodiments disclosed above may be altered or modified and all suchvariations are considered within the scope and spirit of theapplication. Accordingly, the protection sought herein is as set forthin the claims below. It is apparent that a system with significantadvantages has been described and illustrated. Although the system ofthe present application is shown in a limited number of forms, it is notlimited to just these forms, but is amenable to various changes andmodifications without departing from the spirit thereof.

The invention claimed is:
 1. A propulsive anti-torque system for anaircraft, the propulsive anti-torque system comprising: a fixed nozzleassembly comprising: an anti-torque nozzle; a pro-torque nozzle; athrust nozzle; a diverter in fluid communication with a duct locatedinside a tailboom, the diverter having a forward sleeve opening so as toreceive mixed air from the duct, the diverter located forward of thefixed nozzle assembly; a rotating sleeve valve disposed within the fixednozzle assembly so as to receive the mixed air downstream from thediverter, the rotating sleeve valve comprising: a scoop portion having acurved shape concave to the flow of air configured to redirect the mixedair from the diverter into at least one of: the anti-torque nozzle, thepro-torque nozzle, and the thrust nozzle; an actuator configured toselectively rotate the rotating sleeve valve such that the mixed air isredirected in the fixed nozzle assembly.
 2. The propulsive anti-torquesystem according to claim 1, wherein the diverter portion isapproximately concentric with the duct.
 3. The propulsive anti-torquesystem according to claim 1, wherein the airflow through the thrustnozzle produces a forward thrust vector on the aircraft.
 4. Thepropulsive anti-torque system according to claim 1, wherein the airflowthrough the anti-torque nozzle produces an anti-torque vector, therebyproducing a torque on the aircraft.
 5. The propulsive anti-torque systemaccording to claim 1, wherein the airflow through the pro-torque nozzleproduces a pro-torque vector, thereby producing a torque on theaircraft.
 6. The propulsive anti-torque system according to claim 1,wherein the airflow through the anti-torque nozzle and the thrust nozzleproduces a resultant force which is a combination of an anti-torquevector and a thrust vector.
 7. The propulsive anti-torque systemaccording to claim 1, wherein the airflow is pressurized by an engineand a fan.
 8. The propulsive anti-torque system according to claim 1,wherein the anti-torque nozzle comprises: at least one anti-torque vanefor directing the airflow in an anti-torque producing direction.
 9. Thepropulsive anti-torque system according to claim 1, wherein the pro-torque nozzle comprises: at least one pro-torque vane for directing theairflow in a pro-torque producing direction.
 10. The propulsiveanti-torque system according to claim 1, wherein the thrust nozzlecomprises: at least one thrust vane for directing the airflow in athrust producing direction.
 11. The propulsive anti-torque systemaccording to claim 1, wherein the rotating sleeve valve furthercomprises: a sleeve vane located in the scoop portion so as to increasethe aerodynamic efficiency of the scoop portion in turning the airflowinto at least one of: the anti-torque nozzle, the pro-torque nozzle, andthe thrust nozzle.
 12. An aircraft comprising: an engine which providespower to a main rotor system; a fan; a duct within a tailboom, whereinthe duct acts as a conduit to provide airflow to a propulsiveanti-torque system, the airflow being a mixture of compressed air fromthe fan and exhaust from the engine; a propulsive anti-torque systemlocated near an aft end of the tailboom, the propulsive anti-torquesystem comprising: a fixed nozzle assembly comprising: an anti-torquenozzle; a pro-torque nozzle; a thrust nozzle; a diverter in fluidcommunication with the duct, the diverter having a forward sleeveopening so as to receive mixed air from the duct, the diverter locatedforward of the fixed nozzle assembly; a rotating sleeve valve disposedwithin the fixed nozzle assembly so as to receive the mixed airdownstream from the diverter, the rotating sleeve valve comprising: ascoop portion having a curved shape concave to the flow of airconfigured to redirect the mixed air from the diverter into the thrustnozzle and at least one of: the anti-torque nozzle and the pro-torquenozzle; an actuator configured to selectively rotate the rotating sleevevalve such that selectively rotating the rotating sleeve valve redirectsairflow into at least one of: the anti-torque nozzle, the pro-torquenozzle, and the thrust nozzle.
 13. The aircraft according to claim 12,wherein the airflow through the thrust nozzle produces a forward thrustvector on the aircraft.
 14. The aircraft according to claim 12, whereinthe airflow through the anti-torque nozzle produces an anti-torquevector, thereby producing a torque on the aircraft.
 15. The aircraftaccording to claim 12, wherein the airflow through the pro-torque nozzleproduces a pro-torque vector, thereby producing a torque on theaircraft.
 16. The aircraft according to claim 12, wherein the airflowthrough the anti-torque nozzle and the thrust nozzle produces aresultant force which is a combination of an anti-torque vector and athrust vector.
 17. The aircraft according to claim 12, wherein theairflow is pressurized by an engine and a fan.